Without limiting the scope of the invention, its background is described in connection with inkjet printers, as an example.
It is well known to format bitmapped image data for output by a printer, such as an inkjet printer, that scans one or more printheads over a receiver medium, such as a sheet of paper. Each printhead can include a plurality of nozzles, i.e. ink orifices, to allow color printing by printing dots of different colors in proximity to, or on top of, one another. For example, if the “CMYK” model is used, orifices for each of the colors (e.g., cyan, magenta, yellow and black) are used in combination to make various colors. The words “bitmap” and “bitmapped” as used herein refer to a representation, consisting of rows and columns of dots, of a graphics image in computer memory. To display a bitmapped image on a monitor or to print it on a printer, the computer formats the bitmapped data into pixels (for display screens) or ink dots (for printers).
During formatting, the bitmapped image data may be subjected to “pixel swath extraction” in which the pixels (i.e., ink dots) are ordered to be associated with a particular printhead. Also, the bitmapped image data may be subjected to “nozzle data rendering” in which inkjet nozzle drop data is created based on gray scale data or color gamut data Pixel swath extraction and nozzle data rendering is ordinarily accomplished by an image processor, which reads the bitmapped image out of a memory and formats the data in a known manner. Additionally, the image processor can accomplish error correction and diagnostics based on instructions from the computer generating the image data.
Presently, a conventional bitmapped image data formatting apparatus is utilized. Since a single bus interface and a single local communications bus is used to carry both image data and processing instructions, the processor will have many wait states while it waits for image data to be communicated. Further, the architecture in which a plurality of elements (e.g., the bus interface, the processor, and any buffers, accumulators, or other elements) are disposed in a single data path, presents a high capacitance of the system. Both of these factors serve to slow down the effective formatting speed of the conventional apparatus and cause the computer user to wait. Accordingly, a need exists for an apparatus configured to speed up formatting of bitmapped image data for printing.
A need also exists for a device providing separate addressing and control interface, so as to efficiently utilize the time on the device to transfer actual data. Currently, many boards are designed to be general purpose. As such, the boards have one local bus and no separate buffering, causing all peripheral devices and memory devices to be hung off this one local bus. Thus, the one bus exists with more capacitance. Accordingly, a need exists for an apparatus configured to minimize capacitance in order to provide for best data transfer rates.